Uncle Rod's Astro Blog

A quiet little spot where Rod Mollise shares his adventures and misadventures...

Saturday, July 25, 2009

Another Classic

Maybe the classic of the last decade or so. A week or two after I’d finished my survey of amateur astronomy's telescope hits from the Golden Age till now, I had an epiphany: I missed one of the biggies. Which biggie? The Celestron NexStar 11 GPS, of course. What makes that one so good; it’s just another blankety-blank SCT, ain’t it? Just hold your cotton pickin’ horses and we’ll get to that. First we gotta set the controls of that ol’ WABAC machine to the recent past, ‘bout 2001.

That was the year we’d begun seeing new ads from Celestron. Big full color ads introducin’ a new scope that looked a little like the other still new Celestron go-toers, the NexStar 8 and 5, but which obviously had about as much to do with them scopes as a Karman Ghia does with a Turbo Carrera. It was big, an 11-inch, it was imposing looking with a huge dual tine fork mount, and it, we were amazed to read, used GPS. Even at the dawn of this century that sounded WAY high tech.

That Celestron could incite endless speculation and get us all drooling like Pavlov’s pups wasn’t as surprising as it would have been five years previous. Despite being owned by the wacky folks at Tasco at the time, Celestron had just produced its first scopes with wide appeal in years when it brought forth the aforementioned NexStar 8 and 5. Almost everybody liked these CATs. No, they weren’t really serious scopes, some of us curmudgeons opined. They were on the light side mount-wise, and their computer controllers displayed some bug infestation, as might be expected for a first generation computer anything. But they were solid, the go-tos were good, and the 5 and 8 shore was modern-looking--they’d a-been right at home on Kirk’s bridge. These scopes was well received enough that we were all ready for More Better Gooder along the same lines, and here it was, it seemed, starin’ us right in the face from the pages of S&T.

Being the cautious (and cheap) sort I am, I did not jump on the NS11 bandwagon as soon as it rolled into town. I figgered there’d be some bugs to be worked out while I screwed my wallet to the sticking place. Indeed there were, but these seemed few and did not prevent the scope from living up to most of its potential the new owners thought. And there was that undeniable lure for me of the C11. Sure, I love C8s. C5s are nice. C14s are big and cool. But there was always something about Celestron’s Johnny-come-lately OTA that attracted me, some ineffable something beyond just the fact that the scope represented lots of light gathering in a package (theoretically) manageable by one person. Even if that person was a broken down hillbilly like yours truly.

I did a lot of thinking about the scope, waffling back and forth. Two things pushed me over the edge. The first (as you might expect) was money. While the NexStar 11 GPS was not exactly cheap, it was undeniably—even by me—reasonable, coming in at $3000.00 before shipping charges. While a not inconsequential sum, it was really not much more than I’d paid for my Ultima 8 when I allowed for the shrinking dollar and the need to buy “optional” accessories for the U8 like a wedge fine-adjuster kit. The final nail in the pine box for my bank account? A review Bob Berta did of his NS11 for my Skywatch newsletter. It was mostly a glowing one, and Bob was someone whose opinion I trusted. Next thing you know, I was dialing up my good buddies at Astronomics and turnin’ over a credit card number to them.

Naturally, the next week was spent in an agony of anticipation. But it really did not seem like too long before the UPS man was ringing the Chaos Manor South doorbell (AH-OOOOGA!). To be honest with y’all, I’d taken the day off from work to be home when the scope arrived. Not only did I want to get the scope as soon as possible, I figgered we would be talking a BIG BOX, and that it might not be fun loading that into my Camry by myself if I had to drive to Prichard, Alabama and the UPS depot to pick her up.

Yeah, I was on pins and needles, alert as a hound with possum fever. I heard the approach of the brown truck when it was all the way down at the other end of the block, and positioned myself discreetly behind a curtain to see whether the UPS Dude gentled the box out or tossed it off the back. I needn’t have worried. I happened to know the UPS guy on the route on the day in question. He was familiar with the odd boxes that arrived at the old manse at intervals and exercised appropriate caution in their handling. Plus, the bigger of the two boxes...you’d have to be the Incredible Hulk to toss that.

With the boxes positioned in the living room, I set about the task of unboxing (really “uncrating”) new baby. First on the agenda was the tripod, so I’d have something to mount the cotton-pickin’ scope on, natch. This was Celestron’s standard (for the time) “Heavy Duty Field Tripod.” Heavy duty? Well, I used to think so. But the one shipped with the 11 was significantly cheapened and lightened compared to the one that came with the Ultima 8 eight years previous. The rubber coating for the legs was gone. The hardware seemed cheaper. The leg spreader (gasp) was now plastic ‘stead of aluminum. I did not despair, since I figgered that if this thing turned out to be as punk as it looked to be I’d just use the U8’s tripod with the 11. Fishing around in the tripod box, I pulled out something that was nice, yet revealing: a box containing three of Celestron’s famous vibration suppression pads. It was sweet that they’d included these with the 11, but it was also, I thought, an indication they believed the big 11 might be too heavy for the economized tripod.

OK….time for the payoff. Getting the scope out of the box. Opening the big shipping container revealed a spanking new fork mount C11 wrapped in plastic. She had been well protected by contoured foam, and from what little I could see appeared to be in perfect shape. Her upscale and beautiful carbon fiber tube positively gleamed. First sinking feeling: How the hell was I gonna get her out of the box? I accomplished that by grabbing the handle on one of the fork arms, and huffing and puffing and manhandling till I could get a grip on the other arm and gently lower the scope to the floor. My, oh my. I didn’t mean “My, oh my what a good looking scope,” though she was that, but “My, oh, my how in tarnation am I gonna get this thing on the tripod?” A little head scratching and readin of the manual (yeah, me) pointed the way. I had noticed there was only one handle on the fork. That was not actually true. There was only one thing that looked like a handle. The base of the other fork arm was hollowed out. The manual instructed me to insert one hand into this recess, gripping the bottom of the fork arm, and lift while steadying the whole thing with the other handle.

I was skeptical, visions of a smashed corrector dancing in my head. But it worked. Lift up with hand in the fork recess while steadying and applying some pressure with the "normal" handle, and it was possible to lift the 66 pounds of telescope tripod-base high. It was still scary, and once on the tripod I still had to get it in bolted place. It was easy enough to position on the tripod by means of a pin on the tripod which corresponded to a hole on the scope’s base. That done, three bolts had to be threaded-in to secure the NS11. At first that seemed hard, till I realized that lining up indentations on the scope base with the tripod legs would align the holes in base and tripod well enough to allow me—with only a little cussin’ and fine tuning—to get the scope attached to the tripod. I stood up and took a long breath. I’d done it, but, JASPER CHRISTMAS, it had not been fun ‘n easy. I could only hope it would get easier if not easy.

What now? All that remained was to fish hand controller and accessories (a so-so 1.25-inch diagonal, a so-so 40-mm eyepiece, and a standard visual back) and a sweet 50-mm finder (I’d luckily missed the coming of the Chinese finders that replaced the excellent illuminated Japanese models). With everything accounted for, I set down to look at the manual some more. Yeah, I know that is not the sort of thing I’m known for, but heretofore my only experience with go-to scopes had been limited to buddies’ LX200s and a li’l ETX 60 I used as a travel-scope.

When dark finally came, and, amazin’ly enough, clear skies with it, I was ready to go, I thought. At the time our club was without a decent dark site, so it was First Light in the backyard of good, ol’ Chaos Manor South. I set up well before full sunset, since I was still wary (read: SCARED) of the big fork mount, and the last thing I wanted to do was trip over a stray cat in the dark while carrying the humongous thing. I did have to admit that, while the 11 was still a handful, the second time around was a little easier. With NS securely on tripod, it was time to see what she would do with the spring skies. Thankfully, the back 40 was still blessed with some openings in the trees to the East (today, the growth of the big oaks has finally and completely closed out backyard viewing except in the dead of winter).

Connected the Walmart jumpstart battery pack I had bought for the purpose and hit the big switch. In those days, before Meade was able to patent the process of leveling a go-to scope and pointing it north, alignment was crazy simple. Power up. The hand controller told you to press “align” if you wanted to begin a GPS go-to alignment. Doing that started the scope's little dance, leveling itself and pointing north via its electronic compass. That done, the big CAT stopped moving and began listening for GPS SVs to tell it its position and the time. I was a little apprehensive on this score. Minding military GPS receivers is part of my job and I know their quirks. I feared all them trees would keep me from getting a fix. It did take a little while, but I did get one. That milestone accomplished, the scope headed for the first of two alignment stars. Luckily, both were in the clear. Neither was in the finder, but neither was far outside the finder field, either. Despite being new to this go-to bidness, I knew enough from my experiences with my li’l ETX to know not to worry too much about that. Unless stars are half a sky away, center ‘em up and keep on truckin’.

First Light object? Warn’t a whole lot to choose from. My hole in the trees was centered smack on Virgo at the moment, and while galaxies would not be that good a target in the sodium pink skies, you go with what you’ve got. Which one? How about big-daddy fat-spider M87? I hit the “M” key, punched-in 087, and hit enter. The scope hummed and headed east. I was skeptical as to whether I’d hit pay dirt or not, but I sure did like the user friendliness of the NexStar HC as compared to my Autostar. And the quiet, powerful sound of the NS as compared to the LX200’s coffee-grinder symphony. After a while (longer than with my university’s Ultima 2000, I thought), the scope stopped slewing, the little rotating cursor on the HC display disappeared, and it was moment-of-truth time. I pressed my eye to the 12-mm Nagler, looked around the field for a moment, and spotted that unresolved globular-like fuzzball of a galaxy lying almost smack in the middle of the field. Yay.

Actually, it was more like this ol’ hillbilly jumping up and down and letting go a couple of REBEL YELLS! This go-to stuff was, again, new to me and I was still a mite suspicious such a thing could work. My hollering attracted the attention of my young daughter, Lizbeth, who shortly joined me with her Christmas scope, a 6-inch Dob with nice Parks optics my buddy Pat and I had put together for her. We looked at quite a few night-birds all across Coma-Virgo, with Lizbeth taking an occasional peep through the NS11’s finder to help her track down the same prey. Her verdict on the new scope? “Daddy, I like the C11 BETTER. You use my scope for a while!” That suspect tripod? It turned out to be fine, and was so pleasantly light and easy to lug around that I never did get around to using the U8 tripod with the NS11.

First light with Lizbeth had been fun, but I was already plotting a deep sky getaway to see what the scope could really do. Before gettting to that, though, I needed one other item: a case. By 2002, Celestron had long since discontinued cases, but I still needed one; maybe moreso than ever with a big dog—er, “CAT”—like the 11. There were several choices for the NexStar, but I picked a JMI. Yeah, I thought the advertising photos Jim ran in Sky and Telescope, showing a VW bug jacked up on a NexStar 11 case were a bit whacky if attention-grabbing, but what got my attention was the fact that the JMI case had wheels.

Being able to wheel the case out to the car has made the NS11 almost as portable as my vaunted Ultima C8, Celeste,. Yeah, I still have to lift 60+ pounds of Big Bertha and case into the Toyota’s trunk, but that has turned out to be marginally doable. Only downcheck with the JMI is the fact that the finder has to be removed to close the thing. Jim Burr has always been one creative individual, though, and his solution to this problem was a clever one. He designed a little two-piece bracket. One part screwed onto the telescope rear cell. The other onto the finder. With this gadget installed, the finder could be removed by loosening two nice, big knobs. Not only does this bracket make it easy to remove the finder to shut the case, it is so well-designed that the finder's alignment is not affected.

With the case situation resolved, it was time to head for dark skies. By the time I was able to get a few days off from the confounded shipyard, however, star party season in the south was purty much done. Except for one, my Good Buddy Pat noted, the Chiefland Spring Picnic. In due course, then, we were on the famed CAV field along with a couple of hundred other dark sky crazy amateurs. What do I remember most about the Picnic that year? How crowded it was, how hot it was, and how foolish Pat and I were to even think about tent camping on the field. Why we decided to do that, I can’t remember and will never understand. With daytime temps on the field over 100F and the mercury not getting below 80 at night, we sweltered. By 8am it was way too hot to sleep in tents that seemed more like toaster ovens. Before the weekend was over, Unk was bein’ initiated into zombiehood. I resolved that henceforth I would never, ever sleep anywhere other than a motel when at Chiefland.

That was just the annoying part, however. There was also lot of good, starting with our wonderful CAV friends. Most of the time that “wonderful” also applied to the skies. Oh, we was dodging clouds and navigating sucker holes early in the evening, and getting shut down at about 2am, but that is late spring/early summer in the deep south. What was remarkable was how dark and lovely the skies were in-between, and how the NS11 drank it all in.

If nothing else, I was more than satisfied that the computer part of the scope would be consistent and reliable. Every night every object I requested from horizon to horizon was placed somewhere in the field of the 12-mm Nagler. Bertha was just as good optically, producing one of the better star tests I’ve seen in SCTs over the years. I also noted that despite the fairly large primary, focus shift was gratifyingly small. Whatever. I know I saw oodles of cool stuff over that long weekend. What was the coolest thing Bertha delivered? It wasn’t the M13s and M17s and M8s and M20s. What I remember most is what the big cat did to NGC 6712, a normally ho-hum little globular down Scutum way. In the NS11, this ho-hummer became a thing of wonder. Its loose shape amplified beyond imagining with scads of tiny stars set in a field rich beyond belief.

Yeah, I loved my new SCT. But that don’t mean she was perfect. I noticed that when the scope was pointing west of the meridian and tracking in alt-az mode, she would occasionally jerk-jump a wee bit. Just enough to make you wonder what happened, and somewhat disconcerting if you were looking at a rich star field. Turned out there was a bug in the NS11’s motor control firmware (Celestron scopes generally use two computers: one in the hand controller, and a “motor control board” inside the scope). The good part was that C already had a fix. The bad part was that my scope was early enough that my motor control board was not user upgradeable. That turned out not to be a huge deal, since Celestron was quick to dispatch a new MC board to me with the new firmware onboard and which I could upgrade further myself if that proved necessary (and it did…took several releases before all the bugs lurkin’ in the computers was exterminated).

Udder than that? Not a whole hell of a lot to say. The scope has just been completely friendly and reliable over nearly eight years of service. No problems of any kind. But there have been advances. The biggest of which was the introduction of NexRemote. NR is a program that replaces the NexStar HC. You can read all about it h’yar, but the main points are that it adds dozens of features and allows you to use a wireless gamepad as your “HC.” I loved Bertha from the first, but NexRemote made me love her all the more, and has kept her feeling high tech as the observing seasons have come and gone. Even today, not many scopes will, like my Bertha, announce in an Enterprise computer voice “Slewing to target!” and “Target acquired!” and tell me how to conduct a go-to alignment or give me the particulars of the object I’m looking at in a machine-sexy tone.

What’s the deal with the NexStar 11 today? The NexStar 11? It’s gone. The above-mentioned lawsuit in part, I reckon, drove Celestron to introduce a successor scope. In addition to probably being a little cheaper to produce (no carbon fiber tube, for example), the new scope, the CPC, cannot use the verboten north-level alignment routine, even with the aid of NexRemote. Celestron had been paying Meade a royalty for each and every NS sold, and I’m sure they were glad to get out from under it. Yeah, they coulda just modified the telescope’s computers, I guess, but no telescope is forever, and I suppose they decided it was time to move on.

My NS11? We just keep having fun. Last night, for example, we was setup on the Chiefland field once again. While I have a nice wedge for Bertha, I tend to image with GEMs these days. The two things where the NS11 still proves to be on the cutting edge are visual observing and video imaging. Visually, nothing, and I do mean nothing, is as comfortable to use as an SCT in alt-az mode. You can remain seated no matter where in the sky the scope is pointed and just bask in the glories delivered by those luscious optics. Video? The alt-az tracking is good enough to ensure that 10 – 30-second video frames look great, the optics pull in lots of fuzzies, and the design of the scope makes video star gazing a joy.

This past evenig I ran the scope with NexRemote, which was aided by SkyTools 3, which sent the scope goin’ to her go-tos via the same single cable NR uses thanks to NexRemote’s “virtual port” feature. What it boils down to is that I sat in front of the video monitor with a wireless joystick, and sent the 11 to beautiful object after beautiful object. Despite the small chip of my Stellacam 2, all were in the field of my (focal reduced) Bertha. And all were take-your-breath-away lovely. Of late, I’ve sometimes thought I oughta get another, newer big CAT on a GEM, maybe a C14 on a CGE Pro. But you know what? My head is never turned. Every time I get out in the dark alone with my Bertha she makes me forget all about them young upstarts.

Sunday, July 19, 2009

The AstroWebs

It seems like just yesterday that the AstroWeb got cranked up, that amateur astronomy (like many other things) took to that new-fangled World Wide Web like the proverbial duck to water. In reality, it’s been, conservatively speaking, near-about fifteen years since the Internet became a big presence in amateur astronomers’ lives. Starting with things like Archie and Veronica (don’t ask) and the Usenet (if you are wet enough behind the ears to not know what that is, see the entry on s.a.a. below), and winding up with Mosaic and Netscape and that newfangled hypertext WWW, the ‘net and astronomy seemed like they was made for each other, and still do.

What brought this to mind? I was browsing a 1995 issue of my little Skywatch newsletter and ran across my (short) list of great Internet astronomy sites. After I got over chuckling about the quaintness of the list and my naïve speculations concerning the Internet, I decided it might be time for a re-do. Herewith are some—a few—of my favorite Internet venues:

Do you like the deep sky? I mean the DEEP sky? Way beyond the Messier? Beyond even the NGC/IC? If so, Steve Gottlieb and Mark Wagner have the place for you. Their website, subtitled “Challenging Observing Projects for Observers of All Ages,” is just that. Herein, you’ll find guides to the sky’s dusty attic corners, plenty of observing lists, and challenges aplenty (the Aintno list is here). What’s so great, though, is that not only is there plenty of stuff, but that it is presented in a useful and well-written manner. Unless you live out in the southwest desert (or, like Unk, have a Stellacam), you may never get to see all—or even many—of these things, but it sure is fun to read about ‘em.

Another thing I like—nay, LOVE—is minimalist astronomy. As I’ve said a time or three, nothing tickles me more than gettin’ it on with a cheap Chinese scope, some Rini eyepieces, and an old Meade DSI and seeing how far I can push out into the Universe. Andy Raiford thinks the same way, and encourages that sorta philosophy with his website dedicated to “Astronomy and Astrophotography for Non-Gazillionaries.” There’s an awful lot to read and look at. Much of it is dedicated to doing astro-imaging on the cheap, but there’s plenty for the cheapskate visual observer, too, with features on ever’thing from polar alignment to Solar observing. I must also note the very professional design of the page. It looks great and has a lot of video and cool stuff like that. The video, unlike what you see on some websites, ain’t just gratuitous, either; Andy uses it wisely to demonstrate methods and concepts best done with that medium.

Yeah, NASA’s Astronomy Picture of the Day is a more a professional website aimed at the general public than an amateur astronomy page. Many of the images posted daily are taken by spacecraft and professional observatories. And the blurb at the top of the page, “Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer” makes it sound like this site, beloved of just about anybody with even a marginal interest in the Great Out There, is a pro-only NASA public relations enterprise. It started out that way, I reckon, but in recent years accomplished amateurs like Anthony Ayiomamitis have contributed a substantial fraction of the daily pictures. No, I don’t find every day’s pic of interest (how could anybody?), but such a substantial number are that I now have an APOD app on my iPod Touch and keep this wonderful site with me alla da time.

What can you say? Astromart, now owned by Herb York of Anacortes Telescope and Wild Bird fame, is an amateur astronomy institution, and is a measure of how far the I-net has taken us since the days of a certain thin little pulp magazine, The Starry Messenger, which not too long ago was the only source of semi-current astro-equipment classifieds. ‘Course, some folks will say, “Well, yeah, Unk, it’s an institution, but who wants to live in an institution?”

There’s no denying Herb runs a tight ship, and that some people have or have felt they have had their toes stepped on. Yes, Herb and the people who help him with Astromart are only human, and accounts have probably been pulled and ads nixed when they shouldn’t have been. B-U-T…this is usually because Herb and company are erring on the side of caution. A classified ad site is obviously a ripe fruit for the scammers. All you gotta do to see the veracity in that is take a stroll over to the dadblasted eBay. Herb can be draconian, but Astromart is as safe as any venture of this type can be and that is what most of us care about.

Astromart is more than just ads. There’s an auction site, news items, images, telescope reviews, and discussion groups too. Some of these things are popular and some of ‘em have lost a little of their appeal as the number of amateur astronomy related sites has mushroomed over the last five years, but all are well- done and potentially very useful. Astromart as a site is professionally done and easy to use and is and will remain a tremendous resource for amateurs.

If you are like Unk, you like looking at dealer websites, even if you ain’t got the money to buy squat. There are quite a few dealers I like; we are very lucky to be living in an amateur astronomy age where we have almost a surfeit of good guys doing the selling. That said, these outfits are some of the best, and have some of the best web stores. One thing that sets these apart from most of the rest of the pack, though, is how useful their sites are beyond just admiring new gear. Me? I frequently use all of ‘em when I am researching specs for a new book or magazine article. You? All offer some great reference materials that go beyond the what’s-for-sale. Astronomics has a growing library of old telescope manuals for your perusal (and Cloudy Nights). Anacortes has lots of reviews (and Astromart). Orion has always provided lots of tips and explanatory text, especially beginners. OPT, Oceanside Photo and Telescope, has manuals, tip-sheets, and instructional videos. Skies Unlimited has links and a nice newsletter. As for luscious new gear, you can usually see the latest Meade or Celestron wonder a lot quicker on these fine pages than you can at Meade.com or Celestron.com, and that goes for quite a few other makers’ stuff too.

I like Astronomy Magazine’s website. It is beautiful and professionally done. And yet…and yet…some of what is there is kinda ho-hum. There’s a java-based planisphere, editorial staff bios, and some forums. None of these things are compelling or useful enough to keep me coming back. What does? Mostly their fairly recent addition of “subscriber only” features. Login with a password and you will have access to much more detailed star charts (if still not close to good, ol’ Cartes du Ciel), and most engaging, columns by staffers like David Levy and Glen Chaple. Only Standboard Downcheck? They need more web-only content. Still, I think they are on the right track. My principle complaint about the page? Looks overly busy with every frackin’ square inch taken up by scrolling test, animated ads, popups, and polls. Come on guys, it looks cool at first, but wears thin real fast, and I have trouble makin’ heads or tails of the thing some mornins.

This site is here at least partially for sentimental reasons. Back in the old days of the 1990s, this was a vibrant place because, if for no other reason, it allowed those of us without access to the Usenet and s.a.a. to read all them fascinating postings on that “big boys astronomy bulletin board.” Astronomy Mall provided that via a service called “Astro-Net Digest.” This was a frequently refreshed digest of s.a.a. articles. You couldn’t post to the Usenet via this feature, but at the time it was enough just to be able to read the missives of the luminaries who then inhabited s.a.a.—folks like David Levy. After a year or so, Astro-Net Digest disappeared. Why? Some IDIOTS started making noise that Astro-Net was violating some sort of “copyright” by reposting s.a.a. articles. Even in those days when the I-net was new and unknown territory, it seems unlikely anybody would really have been sued for re-posting cotton picking Usenet articles. I suspect the real reason was that whoever was tasked with getting the Digest posted got tired of having to do that.

That didn’t spell curtains for Astronomy Mall, however, and it continues on to this day it its role of providing links to websites of astronomy dealers and vendors. Yeah, some of the big names that used to be there—like TeleVue—have drifted away, but there are still big time outfits like Astronomics featured. Beyond these links? There ain’t quite as much of interest as there used-ta be. There are free classified ads, and for a while I thought these might lead to a renaissance of the site, but let’s face it, when people want to post or read an ad they go to Astromart. I just checked; there was a grand total of 19 active classified ads on the ‘Mall. Still, this is a site that occasionally comes in handy, especially when I’m searching for a small maker or vendor, and one you should prob’ly bookmark too.

I couldn’t resist plugging the web page(s) of my favorite observing site/astro hangout. There have been some changes in the site and in the non-virtual CAV in recent years, but the web venue and Chiefland itself remain welcomingly friendly as always. If you are a member, you will find yourself going to the page frequently. Yeah, it’s simple in design and concept, but all the information you need is there: dates, important news, a Clear Sky Chart. In fact, the main reason I include the CAV here is that it is a model for the “simpler is better” web-design philosophy. You do not have to have tons of video and animation and music and god-knows-what else to make a website go. You need a clear and useable and useful page, and that is just what this is.

Even if you didn’t grow up in the Golden Age of Amateur Astronomy (which, according to us codgers, was the 50s – 70s) you will find this page of abiding interest. Come on, admit it, you’re curious as to why us oldsters’ eyes glaze over at the mention of “Cave,” or “Unitron.” In addition to being educational, you may also decide the scopes themselves are amazingly attractive and interesting and suddenly find yourself embarked on a quest for a mint Super Space Conqueror. Me? Since I do considerable writing about the amateur astronomy days of yore, I find this site exceedingly valuable. What’s here persactly? Just what the title says: .pdf files of instruction guides and catalogs for every major (and many minor) telescope maker from The Day. Only change I’d like to see? More of everything, but especially more manuals. As is, the page is heavier on the catalog end of the spectrum.

Ever’body loves the Clear Sky Charts (formerly the Clear Sky Clocks, before some goober threatened legal action claiming precedence for that name). But most people love it as an embedded display on various webpages or as a desktop gadget or widget. Did y’all know Atilla Danko’s wonderful service, which provides a graphic representation of current astronomy-centric weather predictions for almost anywhere, has a pretty derned good website to go with it? Yep. In addition to allowing you to pull up a Clock (sorry, “Chart”) for the area of interest, it provides detailed instructions for interpreting the Clocks (there I go again), and other cool stuff besides. Hey! Don’t ask questions, just mosey on over; you will be glad you did.

Astromart rules when it comes to classifieds, but when it comes to discussion groups, Cloudy Nights, “CN” to its fans, is where we all go these days. The site was begun a few years ago by a private individual, but didn’t really take off until it was purchased by a major U.S. dealer, Astronomics. People liked the user-contributed gear reviews that had been the site’s stock in trade, but the new regime added professionally written material including not just reviews, but observing articles and mucho other astro-stuff. You can even read this here blog there on occasion. What really turned the key, though, was the discussion groups.

These “forums” are very easy to use, very active, cover a very wide range of topics, and are what keep most of us coming back to CN day after day after day. Right after I check my email in the morning I head right over to the Cloudy Nights boards. And usually stay there for an hour. And usually come back three or four more times before the day is done. Yeah, some folks will tell you the moderating on the groups can be heavy-handed, and there may be some truth to that—at least where one or two of the mods are concerned—but ya gotta take the good with the bad, and this is an incredibly active and popular and valuable resource. Astronomics is to be commended (that is actually too weak a word) for giving us the wonderful CN as we know it today.

If you got started in Internet amateur astronomy back at its dawning, s.a.a., sci.astro.amateur, was not just one of the first amateur astronomy resources on the air, it was, for years, the best. For y’all newbies? s.a.a. was a newsgroup, a forum/bulletin board site on a special part of the Internet, the Usenet, that runs parallel to the World Wide Web. Usenet began in 1979 and survived and even thrived until fairly recently. What was it like in the early – mid 1990s? It was like a rollickin’ 24-hour-a-day astronomy club meeting. Everybody who was anybody in our small world was there: the top writers, the top observers, the folks struggling to produce that new astronomy software. If anything sky-wise or gear-wise happened, you read about it first on s.a.a.

But I’m speaking about s.a.a. in the past tense. Is it gone? No, but it might as well be. I include s.a.a. here for blatantly sentimental reasons. See my blog entry on the subject if you want details, but suffice to say that s.a.a. and Usenet suffered a steep decline as the 21st century came in. Part of the reason was that by mid-decade of the new age there were many, many more places to talk amateur astronomy than there had been, starting with the Yahoogroups and proceeding to Astromart and Cloudy Nights. Also, lots of ISPs began dropping their Usenet feeds. Why? Partially, I reckon, because of legal concerns. Most Usenet groups are, unlike most Yahoogroups, totally unmoderated. In some ways that is great, but folks have, as some folks will, published scandalous and even illegal stuff there since ain’t nobody to say, “I don’t reckon so.” What mostly killed s.a.a., though, was the constant influx of crazies, spammers, and trolls. With many of the best posters having decamped for CN or Yahoogroups, these fools stepped in to pick up the slack. Want a look? Even if your ISP don’t carry Usenet, you can access s.a.a. through Google’s Google Groups site.

These two pages, run by SEDS, “Students for the Exploration and Development of Space” are another couple of examples of the Simpler is Better principle. Neither the Messier nor the NGC database site is fancy, but both are tremendously useful. What’s there? For each object there’s basic data, an image or two, links and more. When I need the specs on NGC-umptysquat, this is where I go. Simple, clear, easy. Bellyaches? Only that I wish there were a little more detail for NGCs and ICs. Their entries are often limited to bare magnitude/positional data, a Dreyer description, and some links. Still, that’s often good enough for me, or at least good enough to get me started, since the NGC pages, like the Messier ones, invariably include hyperlinks to plenty of external data sources if I need More Better Gooder.

Like the other U.S newsstand glossy, Sky and Telescope’s web home looks a little cluttered. Pop ups and animated ads aplenty. Also like Astronomy, though, dig down a bit and you find some interesting stuff. Some real interesting stuff. Most interesting is the web-only content like the “Sky Blogs.” These epistles by Skypub (I can still say “Skypub,” can’t I, even though the magazine is now owned by the blandly named “New Track Media?”) are not only professionally written, they often demonstrate an awareness of the larger world of Internet amateur astronomy, something that used to be ignored by the big monthlies. Most useful of the ‘net- only content for me has probably been the site’s archive of articles from back numbers of the magazine. These .pdf documents, available for a modest fee per article, can be a godsend if you HAVE to have a particular article. I do wish they would make this service free for subscribers, but since I have a huge store of old S&Ts, just using this as an automated index is a tremendous help. The archive appears to be offline at the moment, but I have heard it will return. I hope so. All in all? skyandtelescope.com was one of the first astro-places I visited back in the dark ages when I was logging onto the web via a local “freenet” provider. It is still one of the places I go most.

You want it—when it comes to space, and especially spaceflight oriented articles and media—and this place has got it. Yeah, if you want a wallpaper for your desktop showing M17, or wanna see the Shuttle lift-off, or just wanna keep pace with the repaired HST’s doin’s this is the place to do it. It’s just a shame that the site, owned by the same good folks who publish the Starry Night software, isn’t a little better designed. Hell, it looks like a derned rat’s maze, making astronomy.com and skyandtelescope.com look like paragons of simplicity. There is mucho good stuff here; the problem is finding it. Still, as with the other two, what’s here makes the trip worthwhile.

Do you love your PST? Would you not let a clear day go by without taking a look at old Sol in red or white light? If so, Tony Phillip’s spaceweather.com is the place for you. Hell, it’s worth visiting just for the daily shot of the Sun and the daily Sunspot number. There is a heck of a lot else here too; anything really of worth concerning the Sun-oriented shallow sky is on the page or available via a link.

If you are a seasoned deep sky nut, you are well aware ol’ man Dreyer’s NGC (and IC) is full of problems. Misidentified objects. Missing objects. Non-existent objects. This fine website, which represents years of collaboration between amateurs and professionals, aims to change that—to finally give us a “clean” NGC. There is a lot o’ material here, but what’s of most interest to me, and what will probably be of the most interest to you is the database. Type in NGC Umptysquat or IC Watchamacallit and you will be presented with an image and a cartload of data. The beautiful thing? Thanks to the efforts of the good folk of The NGC/IC Project, you can be purty sure most of what you read is correct. Only bug in the butter? Due to some internal problems (human type problems) this site had to be moved and is still in the process of being reconstructed.

Uncle Rod’s Astro Blog

Yeah, yeah, I know. Here I go tootin’ my own horn again. Howsomeever, I assume that since you are reading this you think my scribblings are of some value somehow to somebody. I am purty pleased at the way this blog has evolved from my random, short, and infrequent entries on the old AOL blogsite to a full-fledged weekly column. How long can I/will I keep it up? As the Astro Blog began to assume its present form, I wondered that too. When would I run out of stuff to talk to y’all about? I ain’t yet, and I’ve got a two page list of potential ideas for articles I ain’t even touched. The bottom-line answer? “I’ll keep the Astroblog going as long as it is still fun and somebody out there is reading it.”

On the dadgummed TV you look at the Weather Channel when you want weather. When you are on the stinkin’ Internet, you use Weather Underground. Yep, Weather Channel has an extensive website, too, but I like Wunderground better. Its predictions seem more accurate to me, I find the site easier to navigate, and I really like the astronomy stuff they feature. Yeppers. Not only can you get the usual sorta junk: Sun and Moon rise, Moon Phases, astronomical twilight times, you can look at a purty little clickable star chart (generated by Distant Suns). I like that. I like the whole site, actually.

The Yahoogroups, née eGroups, Yahoo’s ubiquitous (free) mailing list service, is a fixture of modern amateur astronomy, that’s for dadgummed sure. Before eGroups, putting a mailing list up, an email communications tool where all mail sent to the list’s address is seen by all “subscribers,” was not easy to do. Usually you had to have access to a serious server at a university or some such. And considerable computer know-how. With Yahoogroups, it takes about 5-minutes to get a list going. At heart, Yahoogroups are fun and informative, and I know I have learned one hell of a lot from my own lists, the first of which, SCT-User, I started a decade ago. In addition to being free, Yahoo gives us tools to manage our lists we couldn’t have dreamed of having back in the day of Majordomo.

Every silver lining has a cloud to go with it, though, and so it is with the ‘Groups. It’s so easy to put ‘em up that you can bet somebody has started a group for almost any conceivable subject related to amateur astronomy. I’ve sometimes joked there is probably an “Eyepiece Caps Uncensored” group—and frankly, I wouldn’t be surprised if there were. But ain’t “lots” a good thing? Yes and no. This huge number of groups means the limited number of amateurs is spread thinly over a large number of lists. There is less activity even on the “major” Yahoogroups than there was five years ago, making any one group less vibrant and useful. Another consequence of the growth of Yahoogroups? They pretty much spaded the earth onto s.a.a.’s coffin.

Many, many s.a.a.ers decided the (usually) moderated and (usually) spam-free Yahoogroups were much preferable to the ungoverned (and increasingly weird) sci.astro.amateur, and deserted that uber bulletin board in droves. Is turnabout fair play? I dunno, but in the last couple of years, it appears to me Cloudy Nights has sucked some of the life outa Yahoogroups. Why? Most boys and girls I talk to like the paradigm of having all yer groups in one place and having the ability to jump easily from one to the next. Course, you can’t receive group messages as email as you can with Yahoo, but some folks don’t like that anyhow. Barring a major asteroid strike, though, I believe Yahoogroups will continue to be a daily fixture for me and for most other Internet aware amateur astronomers.

All miffed because you didn’t see your fave site here, are you, Skeezix? Don’t fret. I’m way out of space, and these only constitute the biggest of my biggies, and only those my bourbon soaked brain could recall at the moment. I am sure there will be at least a “Part II” to follow. ‘Specially if’n y’all help jog my memory as to what’s super-duper good out on the Web.

Sunday, July 12, 2009

Zen and the Art of Telescope Collimation.

Unfortunately, for more than a few amateur astronomers, collimation isn't actually an art at all; it’s blood, sweat, and bitter tears. But it doesn't have to be that way. Despite what you may have heard on Cloudy Nights or some other Internet amateur astronomy hangout, collimation just ain’t that difficult. It darned sure is important, though.

If you want good images, especially images of the planets, having the telescope in good collimation, having its optical elements correctly aligned, is critical. If you use a fast (let’s say f/6 or faster) Newtonian, improper collimation will make anything look just horrible—unless you enjoy seeing a field full of “comets” rather than pinpoint stars. SCT owners? Don’t feel left out. Bang-on collimation is equally—maybe even more—important for the good performance of your telescope, and the same goes for the owners of other catadioptric designs. Heck, e’en refractors need to be in proper optical alignment if they are to deliver the goods.

Newtonians

Yeah, most telescopes need collimation, but usually not as often as Newtonians do. For many Newt owners, collimation’s a way of life. Most often asked novice question in this regard? “How often will I have to mess with collimation?” Answer? "That depends." On the telescope’s design. Solid tube Dobsonians, non-truss tube style Dobs, especially those with simple push-pull bolt mirror cells, can go a fairly long time without collimation even if you drive over some bumpy roads on the way to the Bugtussle A.S. dark site. Got a truss tube scope that has to be disassembled and reassembled every time you transport it? Expect to at least tweak the adjustments every time.

Second most common Newtonian collimation question? Do I need a laser? Before we start tweakin’, let’s settle that. Do you need to spend a hundred (or two hundred or three hundred) bucks on a laser collimator to get the scope in perfect optical alignment? No, you do not. One of the ubiquitous Cheshire/sight-tube crosshair collimators available from Orion, Celestron, and others for less than fifty bucks is more than good enough. One of these simple tools will allow you to get even a fast telescope precisely collimated.

Which doesn't mean lasers don’t have advantages. If you are new to Newtonians, you may find it easier to collimate by observing the position of a red laser dot than by trying to sort out confusing reflections, crosshairs, and peepholes. One other advantage of the laser is that if you arrive at the club site late and it’s getting dark, you will find one easier to use than a Cheshire. Oh, you can still use the latter by shining a flashlight into the Cheshire and down the tube, but it won’t be real fun.

What is this “Cheshire/sight-tube” I speak of? A laughably simple tool, a mere metal tube. On one end is a set of relatively thick metal crosshairs. At the other end is a peephole for you to look through. This peephole peeps through an angled silver (or white) surface that is illuminated by a large hole in the side of the Cheshire. There are variations on a theme, of course. Some folks prefer a separate Cheshire and a separate crosshair sight-tube, but the combination model I favor works well and is what I recommend.

Above all, don’t be scared. Some novices have the idea Newtonian collimation is a difficult and involved process that only gurus can master. The reason for this belief is often that Ms. Novice has been reading too many collimation threads on Cloudy Nights. Let a newbie spend too much time reading that stuff (and taking it too seriously), and she or he will wind up like the novice with a new Dobsonian I encountered on the field of a star party where I was doing one of my collimation clinics.

All the conflicting collimation methods and theories and philosophies (and arguments) she had read about had helped her do one thing: get her scope as far out of adjustment as it’s possible to get a telescope. She was on the field sitting next to her new baby in total despair, having given up the idea of getting its collimation anywhere close enough to allow her to observe anything on what had the all the signs of being a perfect evening at a beautiful dark site in the West Virginia mountains.

Instead of immediately laying into her scope, I did as I usually do and told her to forget all the stuff she’d heard about Barlows and lasers and auto-collimators, and just think about what collimation really is. Beyond the fact that it’s getting your secondary and primary in line with each other and the primary more or less pointed straight out the tube, what collimation is is a very simple process involving three things:

1. Center the secondary mirror under the focuser.
2. Center the primary mirror in the secondary mirror.
3. Center the focuser in the primary mirror.

That’s all there is to it, and once I showed her how to use her Cheshire, she was flat out amazed at what a non-intellectual and unskilled activity it is. Collimation is so easy even a caveman—or your Uncle Rod—can do it. Oh, if you are new to all this, the “secondary” mirror is the little diagonally tilted mirror under the focuser. The “primary” mirror is the bigun at the bottom of the tube and is what you paid all that money for.

One more preliminary: make sure the telescope is ready to go. Being ready means there is a mark dead in the center of the primary mirror to serve as a reference for our adjustments. Luckily, almost all modern Newtonians, even inexpensive Chinese Dobsonians, have this mark, usually a paper reinforcer, installed at the factory. If there ain’t one, you need to apply one. Don’t get all worried about that, Mr. Novice. The paper reinforcer will not affect images at all. The big mirror’s center is in the shadow of the secondary, and is not used.

Get yourself a sheet of paper not likely to scratch that pretty mirror, maybe some tissue-type wrapping paper. Use a compass to draw a circle on it the size of the primary mirror. Cut it out and fold it into quarters. Unfolding it will leave crosshair-like creases; the intersection of the creases will define the center of the mirror. Put a small hole there. Now, being careful, remove the mirror from the OTA. Don’t touch the surface, and for god’s sake don’t drop it. Lay the paper circle on the surface of the primary, making sure it and mirror are perfectly aligned, and using a marker or soft pencil, make a small mark through the little hole. Remove the tissue and apply a paper reinforcer (I like the self-adhesive kind) centered on the mark.

Once mirror is back in tube, we can get going with Step One, ensuring the secondary mirror is centered under the eyepiece tube. Insert the collimation tool and have a look. For now, don’t worry about all the funky looking reflections in the primary. Focus your attention on the surface of the secondary. Is it centered under the crosshairs? If it is off “vertically,” if it is rotated, you’ll have to rotate the secondary holder until the middle of that little mirror is smack under the crosshairs. If it looks off horizontally, move the secondary holder back and forth. Either is fairly easy to do with most designs.

Usually, the secondary holder is mounted to a threaded rod secured to the spider vanes (secondary support) with a pair of nuts. If you were off vertically, loosen one of the nuts and rotate the secondary holder until the mirror is centered under the eyepiece and tighten the nut back down. If the mirror needs to move horizontally, loosen the appropriate nut and move the secondary forward or back in the telescope tube until it is lined up. horizontally

Note that secondary mirrors don’t come from the factory with marks at their centers, and most of us don’t mark ‘em. You’ll just have to eyeball the middle, but eyeballing is good enough. Also note that the crosshairs on the end of the Cheshire will look out of focus to your eye. It won’t take but a little use, though, and you’ll easily be able to see them clearly enough. Centering the secondary is normally not something that will need to be repeated often.

After the secondary is centered under the focuser the hard work is done, and we are on to Step Two, adjusting the tilt of the secondary to center the reflection of the primary in it. Looking into the collimation tool, take a gander at the reflection of the primary mirror in the secondary. Do you see the paper reinforcer you went to such pains to paste onto the mirror? Good. Now, take a look the crosshairs. Are they centered on the paper reinforcer? No? Adjust the tilt of the secondary till they are.

How do you do that? It depends on the secondary mirror holder. If you are lucky, the holder will have three small knobs for adjustment. If you are less lucky, it will have three (or sometimes four) Allen screws. Adjust these until the crosshairs are centered on the paper reinforcer. Most secondary adjustment screws work in push-pull fashion. If a screw snugs-up before you’ve turned it far enough, you can loosen the opposite screw(s) to keep tighten the original one more. It is always better to adjust by tightening rather than loosening screws, as that will ensure everything is snug and the hard won collimation will stay good for a long time. The cardinal rule for collimating, however? Always move secondary (and primary) adjusters by small amounts.

We are now two-thirds of the way home. How about that? Is the anxiety beginning to evaporate like morning dew? All that remains is to adjust the primary. Now, we’ll be using the actual Cheshire part of the Cheshire instead of just the crosshairs. Please note that the crosshairs are not shown in the image at left--you don't need 'em anymore. What looks like crosshairs in the picture is the secondary support, the spider. OK, let's get that darned primary mirror done!

Turn the Cheshire in the focuser until there is enough light entering the hole in the tool’s side to illuminate the angled interior surface (don’t point it right at Mr. Sun, of course); you’ll know when the light is sufficient because the reflection of this surface in the primary (as you look through the peephole in the Chesihire) will turn from black to silver (or white). It will light up.

In the middle of the reflection of the Cheshire’s inner surface you will see a round black dot. That is the reflection of the peephole you are looking through. I tried to depict the situation as well as I could in the drawing above (click on it for a bigger version). Your final task is to center that black dot in the paper reinforcer ring. To do that, use the three adjustment knobs or bolts on the primary mirror cell (some imported scopes actually have six bolts, three for adjusting, and three for locking the mirror down--see your instruction manual).

As with the secondary, but even moreso, move each adjustment bolt by small amounts. This is where newbies usually get in trouble. They get way out and start “chasin’ the donut,” that dadgummed paper reinforcer. If that happens, stop, take a deep breath, and think about which way you need to go. Experimentally turn each bolt both ways until you find one that moves the black dot closer to the donut. When it’s as close as it can get using that adjuster (assuming you are not on the money), move on to the next one and turn it a little bit to see if it helps. Try both directions. If that doesn't help, move on to the next adjuster.

In the beginning, it helps to have somebody looking through the Cheshire while you tweak. It can be a godsend to have someone, even somebody not overly experienced in collimation, to tell you, “No, dummy, the other way. Good, now try another one.” Above all, do not get frustrated and turn any adjuster a large amount in a fit of pique (as Unk has been known to do occasionally).

The only common complication when it comes to primary adjustment is that, as above, some scopes, mostly imported Chinese telescopes, have three pairs of bolts on the primary cell. One set is the adjustment bolts, and one set is the locking bolts. Check the manual to see which is which, loosen the locks, and start collimating with the adjustment bolts. One thing I don’t like about this arrangement is that you usually have to collimate twice. On most designs, tightening a locking bolt will change collimation a little, so you’ll have to be careful to tighten all the locks sequentially by small and similar amounts, and keep checking the ol’ Cheshire. If a lock moves collimation, you will have to adjust another lock bolt to bring it back. Yeah, it's like adjusting the primary twice, darnit.

That is all there is to it. There ain’t no more to Newt collimation. Do the above, and your baby will be ready to face any adventure that might befall the telescope tribe. Oh, there’s one more check you can make. When it gets dark, turn the scope to Polaris, insert a medium-high power eyepiece, and defocus the star just slightly until you can see diffraction rings, until the North Star looks like a little bullseye (as in the picture below). Does it look like the bullseye on the right, or is it like the one on the left—squished? If it is squished, adjust the primary by very small amounts until the rings are as concentric as you can make them. Every time you adjust the primary, the star will move off center of course; alwaysre-center it before adjusting further.

Catadioptrics

Schmidt Cassegrains

Newtonian adjustment, as we’ve seen, is just three lousy little steps. Not hard or bad at all. If you are an SCT owner, collimation gets even easier. You have only one measly step. You really do have to do it, though, since good collimation is even more critical for good SCT performance than it is with a fast Newtonian. “Why is that Unk Rod, huh, whyizthat?” Because an f/10 SCT uses a 5x magnifying secondary mirror to up the focal ratio of the scope’s fast f/2 primary mirror. That magnifying factor tends to exaggerate small errors in collimation.

OK, it’s important. How do you get started? The first thing to do is put away the collimation tools. Step away from that Cheshire. Because of the mechanical design of commercial SCTs, a Cheshire will almost always guarantee a badly mis-collimated telescope. OK. A laser then? Same-same. You will find laser collimators designed for use with SCTs, but they don't work well or at all (with the exception of the Hotech Advanced CT collimator, which might be a bit much for a novice to handle). With a Schmidt CAT, you need to do the adjustment the old fashioned way.

Actually, there is one collimation tool you use with an SCT. The good news? It is free: Polaris. Yes, you can collimate an SCT using an artificial star of some kind, but Polaris is easy and available every clear night in the Northern Hemishpere (if you are south of the Equator, just use any star of about magnitude 2).

I said collimation of an SCT only involves one step, and that is technically correct. The only user-adjustable element in Meade and (modern) Celestron SCTs is the secondary mirror. And that is all that needs to be adjusted for perfect collimation and performance. We can, however, break the process of doing that into four steps:

1. In the Ballpark
2. Rough
3. Fine
4. In-focus

In the ballpark. Most of you will be able to skip this step. The only reason to do “in the ballpark” is if your scope’s collimation is so far off that stars look like comet-blobs or worse, and it’s impossible to get it “in” using Polaris. I’ve seen novices get their CATs in this condition once in a while. Luckily, picking up the pieces is easy. Adjust the scope’s aim until you are looking straight down the tube from about two meters away. Observe the series of reflections of primary, secondary, and baffle tube. Is it all concentric? Does everything line up, or is the reflection of the secondary in the primary tilted off to the side? If it is, adjust collimation until it all looks centered. How?

You’ll find three Allen or Phillips screws on the secondary holder. Adjust these just like you did the screws on the Newtonian’s secondary: tighten by small amounts, and, only loosen opposite numbers to continue in the proper direction. Please note, y’all, that some older Celestrons have orange plastic covers over their secondary adjustment screws. Pop the cover off by gently prying with a screwdriver and put the thing away in a drawer somewhere. A few newer Meades may have three pairs of allen screws; see the manual for details as to which is which and what for. Caveats? The only one is that you must never fully loosen all three screws at once. Do so, and the secondary mirror will go KER-PLUNK on the primary.

Rough. You are in the ballpark. Now comes rough collimation. Point the scope at Polaris and center the star carefully. Insert a medium-high power eyepiece. Defocus until the star looks like a Krispy Kreme, until you have a big white donut with a dark center. Is that dark center, the shadow of the secondary, in the middle or is it off to the side (before deciding that, double-check that the donut is as centered in the eyepiece as you can get it)?

If it is off to the side, adjust the collimation screws until the donut hole is centered. Which screw should you turn? At this stage of the game, I just pick one and tweak it a smidge. If that doesn’t move things in the proper direction, I switch to another. When the donut looks good, move on to the meat of the matter, fine collimation. Yeah, I know some folks stop with the donut, but that is rarely good enough for exacting tasks like high power planetary observing. Besides, if you are going to go to the trouble of doin’ the job, you might as well do it right.

Fine Collimation. Re-focus Polaris until it is almost sharp. Until it looks like the series of concentric bullseye rings. Once again, make sure it is as precisely centered in the field as you can get it. The rings are not concentric? They are squished on one side? You’ve got more collimating to do, muchacho.

What’s that? The bullseye is jumping around and boiling so much you can’t tell if the rings are concentric or not? If you think it’s the seeing, you can either wait a while and see if it settles down, or throw in the towel for the night. If the stars ain’t twinkling madly, the problem may be cooldown. If you just brung Miss Scope outside, give her a while to acclimate. How much power should you use for this stage? I like about 150x or so.

Time to finish up. If the bullseye is squished, you’ll adjust the secondary screws until it is unsquished. Which screw do you move? You could pick one like you did before, but this is more exacting work than rough collimation, and it can help to have a system. Lots of folks use lots of different methods to determine “which one.” Me? I like to keep things simple, so I use a slightly more complex variation of my low tech “pick one” strategy.

Look at the bullseye. Which side is squished? Move the star until that side is against the edge of the eyepiece field. Now, turn the collimation screws by small amounts until you find the one that moves the star toward the center (again, moving a collimation screw will move the star in the field). Use that screw (or screws, if necessary) to move the star back to the middle of the field. Keep moving the star to the field edge and re-centering it with the screws that until the rings form a perfect bullseye.

I’ll say this one more time: tighten screws to collimate. Only when a screw is snug should you loosen its opposite number(s). Usually you will then be able to turn the original screw some more. Doing that will ensure your scope stays in collimation—for months, or maybe even years. When I hear that an SCT owner is having trouble keeping their scope in collimation, not having at least one collimation screw snug is usually the problem.

I mentioned four steps, though. If you have very good seeing you can kick things up a notch with in-focus collimation. Center Polaris and bump the power up, to 300x or more, high enough so that when the star is in perfect focus you can see its Airy disk and first diffraction ring. Take your time and examine that first diffraction ring closely. Is it unbroken around the Airy disk? Just like the one on the right in the picture? Or is it broken? If it ain’t complete around the disk, your job is to move the collimation screws by tiny amounts until it is. Obviously, you’ll need a light touch and a steady sky to do this, but if you’ve a yen to look for Saturn's Encke Gap/Minima at 500x with your C8 (I’ve done that successfully), you need to get collimation as dead-on as you can, and in-focus adjustment is how to do that.

I said “no” to lasers and Cheshires for SCTs. Are there any accessories that help with SCT collimation in any meaningful way? Some new SCT owners replace their telescopes' allen or phillips screws with knob-headed bolts, either from the hardware store or from a commercial vendor, Bob’s Knobs. Do you need to do this? My verdict is "not necessary." If you collimate correctly, it will be a long time before you have to do so again, so the original screws are more than good enough. Some novices worry about having a screwdriver in close proximity to the corrector. This is not a big problem--I've yet to hear of someone scratching their corrector during collimation. Just take your time and take care.

What has caused problems for more than a few novices? The process of replacing the telescope's original collimation screws with knob-headed ones. Bob's Knobs come with excellent instructions, but some newbies have gotten into trouble during the procedure, nevertheless.

Schmidt Newtonians

A Schmidt Newtonian is like a Newtonian, but also like an SCT. What one is is a Newtonian without a parabolic mirror. The SNT uses a spherical primary, which would normally leave Saturn or anything else looking like a custard pie due to spherical aberration. To banish that, the SNT uses a corrector plate (lens) just like an SCT. Collimation? You adjust a Schmidt Newtonian just like you do a Newtonian. There is one small fly in the ointment: if the secondary has become rotated on one of Meade’s LXD 55/75 SNTs (the only ones out there in significant numbers today), the corrector lens to which it is attached may have to be loosened and rotated slightly to center the secondary under the eyepiece.

Maksutov Cassegrains

There are two possible collimation realities here: easy like an SCT, or potentially difficult. There are two MCT breeds, you see, Gregory Maksutovs and Rumak Maksutovs. Gregorys (or is that Gregories?) do not have a separate secondary mirror; instead it is an aluminized spot on the inside surface of the corrector. These scopes can be collimated, but it is sometimes not easy. The Meade ETXes, for example, require the disassembly of the rear cell to access pairs of push pull bolts that allow the primary to be adjusted. Not fun. The Synta-made Gregory MCTs Orion (and Skywatcher and others) sell, on the other hand, have exposed primary collimation bolts on the rear cell. To collimate a Gregory MCT, you proceed as you would with an SCT, just adjusting primary rather than secondary.

How about the Rumaks, which include the Intes-Micro MCTs? They have separate secondaries in holders just like SCTs, and are collimated the exact same way they are. If I had my choice, I'd take a Rumak. While the Gregory scopes can be collimated, it's sometimes more difficult than it would seem for several reasons. If you want "perfect," it can be, as telescope guru Roland Christen has said, a job for a trained technician and an optical bench.

Maksutov Newtonians

You don’t see many MNTs these day, despite the fact that they can be excellent telescopes. It's likely because they tend to be heavy for their apertures and a bit expensive compared to other designs. If you do glom onto one, you’ll find they are worked the same way as an SNT; you collimate ‘em like a Newtonian.

Cassegrains

For the longest time, there not much need be said here. Non Schmidt and Maksutov Cassegrains were almost extinct in the amateur world. Those few worthies with Dall - Kirkhams and Richey Chretiens and Classical Cassegrains were almost always in the “advanced amateur” brigade, and knew how to collimate their telescopes. Today, that’s less the rule as inexpensive RCs fall into the hands of us rank and file amateurs. What do you do? Mostly you follow the directions for your specific telescope as outlined by the manufacturer in the manual.

What’s collimating these scopes like? I’ve done a Classical Cass or two and it ain’t no Classical Gas. The combination of an adjustable primary and an adjustable and strongly magnifying secondary mirror supported by a spider makes things, shall we say, "interesting." The inexpensive GSO Richey-Chretiens (sold under a variety of brand names) in particular can be a pain. While they've been improved, their still somewhat deficient mechanical design can make collimation a hairline reducing and blood pressure increasing experience.

Refractors

Yeah, how about refractors? As you’ve no doubt been told by their fans, most will never need collimation. Most. Those that do? If it’s a pricy APO, the best bet is probably letting the maker do it. A Synta achromat with an adjustable cell? A Chehsire will make short work of that. Insert Cheshire and look in. Observe the reflection in the objective inner surface of the black dot (the peephole). Is there only one? Cool. If not, collimate until the two reflections of the peephole merge into one. Finish up with a diffraction ring collimation on Polaris.

If your refractor doesn't have an adjustable objective cell? Often there's enough play in the screws/holes that hold the focuser to the tube to allow you to collimate that way, by loosening those screws and tilting the focuser assembly one way or another--that's how I adjusted my old Short Tube 80. Such a collimation is not likely to be very precise, but you should be able to get close enough.

That does it. Now, you tell me, does that sound so bad? No. Is your scope in perfect collimation? Find out tonight (or this afternoon if you are not a CAT user). If it ain’t, make it so. I guarantee you will thank me the next time you get it out under the stars. If your babe has been in iffy collimation for a while, or maybe even forever, I guar-ron-tee it will be like havin’ a new scope. You may even decide your lemon is really a PEACH.

Sunday, July 05, 2009

The Urban Astronomer

I know I’ll probably be accused of tootin’ my own horn over this subject, but it’s one that’s near and dear to my (just slightly withered) little heart and would be even if the Urban Astronomer story hadn’t culminated in the publication of my 2006 book, The Urban Astronomer’s Guide. There’s a lot more to it than just the book, you see; that’s the cherry on top. The real story is my long struggle to see something of the deep sky from the most light-polluted backyards and how I learned to do that. And how you can too. That’s something the urbanites and suburbanites among y’all might find of value, I reckon. Besides, what good’s having your own blog if you can’t toot your horn—or plug a dadgummed book—once in a while?

No, the Urban Astronomer story didn’t begin in 2006, but in 1967. That hallowed summer, the Summer of Love, was a big one down here in The Swamp. The excitement was in no way related to what was going down out in the Haight, however. The big talk here was that we was finally gonna get us a Mall. Our shopping scene had been unchanged since—well prob’ly since forever, or at least since the founding of our little burg in 1711. When your mama got a yen for a new dress, or daddy wanted a new fedora, you headed downtown (with Mama in hat and gloves and Daddy in coat and tie), to Dauphin Street, where you visited merchants whose venues (and probably their stock) hadn’t changed much since Dauphin Street was paved. But, hey, come on, this was THE SPACE AGE! Time to GET WITH IT, DADDY-O.

How we, sprouts and oldsters both, looked forward to our very own Mall. And how wonderful it was on opening day late that summer. Strolling in air conditioned comfort while gaping open mouthed at the modern marvels on display (I saw a Nehru jacket in the window of—omigod—was that place one o’ them HEAD SHOPS?). Hell, The Mall even had a big bookstore that, unlike The Haunted Bookshop downtown, was lighted well enough so as you could actually read the titles of the books (I begged the money outa Mama for Alan Nourse’s Trouble on Titan).

The time would come when we realized THE MALL had killed our vibrant downtown, and eventually some of us would pine for it and try to get it back. Today, The Haunted Bookshop at least is alive and well again as The Haunted Bookloft upstairs at Bienville Books. Turned out there were more unintended consequences to the mallification than just turning Dauphin Street into a depressed area, though.

I know you sprouts get sick of old timers telling y’all how good the skies was “back then” (whenever “back then” was). I ain’t gonna do that nor sugar-coat the way things really were for most of us. Even in 1965, my suburban backyard sky was not perfect. When it’s as humid as it usually is down here you can never, ever have perfect deep sky viewing year round. The 1960s sky was nice and black in winter (I still couldn’t see the Horsehead with my Palomar Junior), but in the summertime, despite a scarcity of mercury vapor lights, poor Scorpius’ tail was cut off when the stinger was anywhere near to the horizon. I could see the Milky Way as it approached zenith, but it was not always prominent. M27 showed off its apple core self in the Pal, M13 could be big (if unresolved), and the Lagoon, M8, was sometimes more than just a dim glow around a dim star cluster. The irony? This was to be as good as it ever got for me from home.

At first I thought it was just my imagination, but the spring following the Summer of Love the sky just didn’t seem as dark as it had been the three previous years of my amateur astronomy career. Leo still sprawled across the eastern horizon, heralding the return of the great forest of galaxies that stretches from northernmost Canes Venatici to southernmost Virgo, but he was a little subdued. His hindquarters were hard to make out early in the evening when that triangle of stars was low on the horizon. Those marvelous night birds, M65 and M66, were not looking any better in the homebrew 6-inch Newt I was now using than they had the previous spring in the Pal. Hmmm…

What lay to our east? A scant few miles that-a-way was the wonderful mall and its hundreds of mercury vapor lights, which were spawning hundreds and thousands more as that Mecca begat new Pizza Huts and Western Sizzlers aplenty and a huge clutch of older businesses decided it was high time for them to desert downtown too. Final coffin nail for the folks’ backyard? Power company trucks fanned out across the neighborhood in the fall of ‘68 and there was soon an accursed streetlight on every other power pole (well, seemed like). Heretofore, I’d had to deal with exactly one light three houses down on the corner. Now there was one in our front yard. Did I panic? Did I give up the deep sky? Did I persevere despite the “light-pollution” (I don’t think we’d coined that term just yet)? None of the above. Before either despair or resolve could set-in I was off to college and then the Air Force, and was eventually luxuriating in the spotless skies of northern Arkansas.

I saw lots of cool things in Razorback Country, but that is a story for another time. For now, let’s fast-forward to the mid 1980s when I found myself back in Possum Swamp as not just a civilian, but as a married civilian. For a while I was too busy setting up housekeeping and getting oriented in a new career to spend much time observing or even thinking much about it. ‘Course I kept my hand in, but in addition to the travails of learning the ropes as the new engineer on the block, I shortly realized I had a wife who was, as Harlan Ellison once spoke of one of his marital mis-matches, more alien than any of them green skinned women Jim Kirk used to court and not one half as tractable. After a year or two I sensed the marriage was spinning out of control and taking me down with it. Following some semi-serious attempts to pull out of that nose dive, which only resulted in the wings coming off, I spent a considerable length of time in that odd interlude that passes in quite a few failing marriages before the end.

This intermission manifested in me spending increasing time with my old and steady friends, the stars. A couple of hours under their calming influence, basking in the sure and steady knowledge that they’d continue in their courses no matter what, made my problems seem trivial. This despite the fact that so many of my friends were invisible from my midtown backyard. The light-pollution was frankly horrendous. No, maybe not as bad as Chaos Manor South’s environs today, but I didn’t have the option of a week in Fort Davis or a weekend in Chiefland or a night at the club dark site. Even the oblique hint that I intended to take off with the scope resulted in screaming fights. For a time, I would have to be satisfied with the stars as they were.

That seemed impossible. You know, look north and you see Polaris and the two brightest Little Dipper bowl stars and nothing else. To the east? Sodium Pink up to 40 degrees. West? Almost as bad. South? Marginally better if at all. Sure, I could have contented myself with Luna and the rest of the neighborhood gang, but… You can spend a lifetime observing the Moon and Mars and Jupiter and Saturn, but I was hungry. Hungry for the deep sky after years of deprivation.

One semi-dark and Moonless winter’s night enough finally became enough and I set up my Super C8 Plus in the bright backyard and had a look at Orion—at M42. “Well, well, well.” Not nearly as bad as I’d a-thought. No, I couldn’t make out M43’s comma shape, and the field of my Erfle wasn’t exactly full of nebulosity, but the Great Bird of the Galaxy spread his wings nevertheless. Good? It was wonderful. How about M78? Only one puff of nebulosity was apparent, but it was there. So was M79 down Lepus way, who even gave up a few stars to my Circle T Ortho. Soon I was cruising the Messier, missing nary a one with the C8 or even the Pal Junior. If I was patient and waited for just the right night, even the M101s and M74s fell before my wondering eyes.

Naturally, I was pumped and was soon making lists that contained not just Messiers, but NGCs too, and not just NGC open clusters, but galaxies dim enough to be, I feared, impossible in my compromised skies. Except many of ‘em weren’t. Most of the dimmer stuff was nothing more than cosmic dust bunnies in the eyepiece, but was there nonetheless. I began to wonder if there might be techniques or equipment that would allow me to see the surprising amount of things I could see better. A “literature survey” of my considerable store of astronomy books and Sky and Telescopes and a visit to the downtown library, which had a good if not overwhelming collection of amateur astronomy books, turned up—squat. The only mention I could find of deep sky observing from heavily light polluted urban and suburban locales was the admonition: “Don’t!” Of course, some observing tips are as good from bright skies as they are from dark skies, and when I thought about it, I realized I’d already started usin’ my own set of tools, which I sat down and formalized one stormy night:

Protect yourself from ambient light. This is the biggie. Ambient light, the light falling directly on your observing position from nearby sources—Miss Ellie’s back porch light, the sodium vapor light right out front, the glow from your own back window—is at least as damaging when it comes to seeing deep sky objects as is the general sky glow. If you could obtain at least a modicum of dark adaptation, you could see much more of the deep sky under the worst light-pollution than you can with your pupils constantly pinned. The good thing is you can do something about ambient light.

You may not be able to convince Ol’ Miss E. to turn off her porch light for even an hour, but you can rig up light shields to keep your scope and you in shadow. These can be anything, but stage-flat-like shields can be made easily and work particularly well since they can be moved around the yard as you move the scope to avoid trees and other obstacles. Don’t want to go to that much trouble? A dark cloth draped over your head when you are observing, and an eye patch to protect your dominant eye when you are not, will do as well, even if you might cause the neighbors to doubt your sanity if they notice you prowlin’ the backyard with your pirate eye patch and cannon.

Get a great big finder, a set of digital setting circles, or just go go-to. This is almost as important as the previous “rule.” Lots of deep sky stuff looks cool even from the worst skies, and much of it is easy to see with a 6 or 8-inch telescope. The problem is finding it. If you habitually locate objects by starhopping, you’ll be stymied by a lack of stars in the urban sky. A Telrad, for example, might not show any stars between Virgo’s arms (between Epsilon and Beta Virginis, I mean). That whole area is just popping with island universes, but good luck locating ‘em when there are no guide stars visible.

So? You forget the Telrad or use it in concert with an optical finder, which will show many stars invisible to the naked eye. A 50-mm is OK, an 80-mm is better. Much superior in my opinion, though, is a set of digital settin’ circles or a go-to scope. If you’re a dyed-in-the-wool star hopper who’s secretly been curious about computerized finding, urban observing is a good excuse to get your feet wet in 21st century amateur astronomy.

Pump up the power. I know you love your 35-mm Panoptic. I love mine too. But not in the city. In areas of significant light-pollution, the background sky-glow in a low power eyepiece is bright enough to extinguish your prey. In the city, my usual “low” power is about 100 – 125x. Yeah, I know that goes against the grain. You are supposed to use low power for deep sky observing, right? Well, no. Even under dark skies, many amateurs use way too little power on the deep sky. Higher power will frame many objects better (there are way more medium-small galaxies and planetary nebulae and globs than there are giant open clusters and emission nebulae) and will make it easier to see minute details. More importantly for the urban astronomer, higher power spreads out background sky-glow enough to make the quarry pop out.

Naturally, you’ll need to experiment to find a magnification for use in your skies that enhances the contrast between sky background and objects without making targets too dim, but a few fun nights playing around with your eyepiece collection will reveal the sweet spot. My fave? In the days before the 13-mm Ethos it was the 12-mm Nagler 2. Enough power in my 12.5-inch f/5 to enhance DSOs, but enough field to allow me to “eyepiece hop” in crowded areas like Virgo.

Wait for it…wait for it… Objects that are invisible one night may be visible the next if the humidity drops. Or if you wait till after midnight when some city lights go out and the skies get a little better. Or if you wait till the object culminates (crosses the local meridian) and is as high in the sky as it ever gets. Or you cool your heels until M101 or M74 or M97 gets over toward the good side of the sky away from the light dome. In other words, don’t declare anything “impossible” from a bright backyard until you’ve tried for it on multiple occasions under multiple sky conditions.

Other tips? I could keep going, but if you find these useful and want more, I (ahem) commend The Urban Astronomer’s Guide to you. The first half of the book is devoted to urban observing techniques and equipment choices (the second half is a collection of deep sky “tours” for every season of the year). But I’ll betcha some of y’all are still scratching your heads. Why would anybody try to see anything of the deep sky from city lights? Even if you’re like me (these days) and have a wonderful and understanding Significant Other who not only encourages you to get to deep and dark sites, but often accompanies you on these expeditions, you may nevertheless still want to hit the sodium pink backyard regularly.

Unless you are blessed with dark skies at home or are retired or independently wealthy, it’s likely your career(s) make dark site observing a once or twice monthly thing. The weather often changes that to “every few months.” After a stretch of clouds, I often find myself wasting time when I finally get back to good skies. Where the heck is Piscis Austrinus? Which eyepiece was the one that worked so good with NGC 2024? Whar’s that confounded red flashlight? That greatest of all amateur astronomers, Sir William Herschel, once compared observing with a telescope to playing a musical instrument, and I think that is right apt. How good would you be on the steel guitar if you only practiced every few months? Even if your backyard ain’t exactly a showpiece, you get out there and you practice. That will, if nothin’ else, pay dividends the next time you get out to the Prude Ranch or jus’ the Mount Pilot Astronomical Society dark site.

How did I go from doing the Messier from a bright backyard with a Pal Junior to writing a cotton pickin’ book about the art of urban observin’? It didn’t happen overnight. The first step on the road was when I decided to see if I could do all the Ms with the 4-inch Edmund. I thought it would be fun to keep a logbook of my efforts and draw each of the objects I was able to corral. In a couple of years I’d done ‘em all by means of patience (and maybe a little averted imagination). I enjoyed the hunt and was proud of my resulting logbook. Which led me to wonder what I could do with my writings and drawings now that I was done. Coincidentally, the Editor of Skywatchback then (no, believe it or not, I wasn’t always that person) was desperate for something/anything to put in the next issue. I said I wouldn’t mind writing-up a piece, maybe even a few columns, about my urban observing experiences, and I soon got to work hacking out a short spiel on M94 on my IBM with the aid of Wordstar.

The “few columns” eventually stretched over five years. The format was almost always the same: I’d pick a constellation or two and an object or three and describe how to find ‘em and what they looked like in the city. Along the way, I’d throw in a few tips not unlike those above: “If your skies are as bad as mine, NGC 5195 is going to look like a small, dim blob. Use medium power and expect to have to use averted vision on bad nights.”

When I started the series, which I called “From City Lights to Deep Space,” I did it to help my buddy. Soon I found I was doing it to please myself; I enjoyed spreading the word about urban observing and writing about the deep sky. Eventually, after I took over Skywatch and started posting it on the web, I began doing it to please the fans the column had garnered. When did I know “City Lights” was destined for bigger and better? When my readers began writing and emailing requesting copies of all the “City Lights” columns. I prob’ly printed, stapled together, and mailed upwards of 500 copies of the resulting “book,” most often gratis. So, when Springer and I got to talking about my Next Book, I mentioned this crazy idea I’d had cooking for years…

I expected to be told my idea was ridiculous, that nobody would be interested in a book on urban deep sky observing. Instead, Springer was supportive, even enthusiastic. Their only stipulation was that I change my proposed title. “From City Lights to Deep Space,” they thought, wasn’t scientific sounding enough. I suggested a number of possible titles, with my Editor and his bosses settling on The Urban Astronomer’s Guide, which I didn’t like that much, but was, I admitted, OK. It would be easy to say the book wrote itself, and in some ways that is true. I was passionate about the subject, and the words flowed. But that don’t mean it wasn’t a hell of a lot of work. Any book is, with the most onerous part of the process being the constant need to Apply Seat of Pants to Seat of Chair and write for a couple of hours. Every day. Day after day.

It sure was worth it. I am satisfied with my other books, but Urban Astronomer (I almost typed “City Lights”) is and will remain closest to my heart. If you should feel inclined to buy a copy, you’ll soon realize it ain’t perfect. I was frankly still learning the craft of book writing even at that late date, and in this age when competent copy editors are becoming an extinct species, it’s no surprise there are a more than a couple of mistakes to be found.

What did you all think? Ain’t nobody gonna start callin’ me “Stephen King,” and I ain’t gonna quit my day job, but the book sold OK and continues to sell OK in a smallish amateur astronomy book sorta way. When all is said and done, I’m happy with the result, and that is a lot for any author to say. I’m still passionate about the subject, too, maybe even moreso than I am regarding my never-ending quest to get the pore ol’ Schmidt Cassegrain the respect it so richly deserves. “Urban Astronomer,” you see, ain’t just some book the world will little note nor long remember; it is a state of mind. A state of mind that proclaims I WILL SEE. No matter what the obstacles I WILL SEE—every clear night.